Pyocyanin as anti-tyrosinase and anti tinea corporis: A novel treatment study.

OBJECTIVE: The aim of this study was to evaluate the efficiency of pyocyanin pigment as a novel compound active against tyrosinase with its depigmentation efficiency for combating Trichophyton rubrum which could be a major causative agent of tinea corporis. METHODS: Fifty swabs of fungal tinea corporis infections were collected and identified. Five MDRPA isolates were tested for their levels of pyocyanin production. The purified extracted pyocyanin was characterized by UV spectrum and FT-IR analysis. Pyocyanin activity against tyrosinase was determined by dopachrome micro-plate. In addition, the antidermatophytic activity of pyocyanin against T. rubrum was detected by radial growth technique. In vivo novel trial was conducted to evaluate the efficiency and safety of pyocyanin as an alternative natural therapeutic compound against T. rubrum causing tinea corporis. RESULTS: Purified pyocyanin showed highly significant inhibitory activity against tyrosinase and T. rubrum. In vivo topical treatments with pyocyanin ointment revealed the efficiency of pyocyanin (MIC 2000 µg/ml) to cure tinea corporis compared to fluconazole, which showed a partial curing at a higher concentration (MIC 3500 µg/ml) after two weeks of treatment. In addition, the results revealed complete healing and disappear of hyperpigmentation by testing the safety of pyocyanin ointment and its histopathological efficiency in the skin treatment without any significant toxic effect. CONCLUSION: Pyocyanin pigment could be a promising anti-tyrosinase and a new active compound against T. rubrum, which could be a major causative agent of tinea corporis. In fact, if pyocyanin secondary metabolite is going to be used in practical medication, it will support the continuous demand of novel antimycotic natural agents against troublesome fungal infections.

Reduced expression of virulence factors in multidrug-resistant Pseudomonas aeruginosa strains.

MDR Pseudomonas aeruginosa strains are isolated from clinical specimens with increasing frequency. It seems that acquiring genes which determine antibiotic resistance usually comes at a biological cost of impaired bacterial physiology. There is no information on investigations comparing phenotypic differences in MDR and MDS P. aeruginosa strains in literature. The study included 150 clinical P. aeruginosa isolates (75 classified as MDS and 75 as MDR). PFGE analysis revealed five pairs of identical isolates in the group of MDR strains and the results obtained for these strains were not included in the statistical analyses. MDR strains adhered to polystyrene to a lesser extent than MDS strains. The growth rate in the liquid medium was significantly lower for MDR strains. Detectable amounts of alginate were present in the culture supernatants of seven MDS and six MDR strains. The MDR P. aeruginosa strains which were investigated produced significantly lower amounts of extracellular material binding Congo Red, lower lipolytic, elastase, LasA protease, phospholipase C activity and pyocyanin quantity in culture supernatants when compared with MDS strains. No significant differences were observed between MDR and MDS strains in proteolytic activity. In conclusion, the MDR P. aeruginosa strains have impaired virulence when compared to MDS strains.

The bacterial redox signaller pyocyanin as an antiplasmodial agent: comparisons with its thioanalog methylene blue.

The quorum sensor and signalling molecule pyocyanin (PYO) contributes significantly to the pathophysiology of Pseudomonas aeruginosa infections. Comparison to phenothiazine drugs suggests that the antimalarial compound methylene blue (MB) can be regarded as a sulfur analog of PYO. This working hypothesis would explain why the synthetic drug MB behaves as a compound shaped in biological evolution. Here we report on redox-associated biological and biochemical properties of PYO in direct comparison to its synthetic analog MB. We quantitatively describe the reactivity of both compounds toward cellular reductants, the reactivity of their reduced leuco-forms towards O2, and their interactions with FAD-containing disulfide reductases. Furthermore, the interaction of PYO with human glutathione reductase was studied in structural detail by x-ray crystallography, showing that a single PYO molecule binds to the intersubunit cavity of the enzyme. Like MB, also PYO was also found to be active against blood schizonts of the malaria parasite P. falciparum in vitro. Furthermore, both compounds were active against the disease transmitting gametocyte forms of the parasites, which was systematically studied in vitro. As shown for mice, PYO is too toxic to be used as a drug. It may, however, have antimalarial activity in numerous human patients with concomitant Pseudomonas infections. MB, in contrast to PYO, is well tolerated and represents a promising agent for MB-based combination therapies against malaria. Current and future clinical studies can be guided by the comparisons between MB and PYO reported here. Additionally, it is of interest to study if and to what extent the protection from malaria in patients with cystic fibrosis or with severe wound infections is based on PYO produced by Pseudomonas species.

Parasitological, hematological and ultrastructural study of the effect of COX-2 inhibitor, pyocyanin pigment and praziquantel, on S. mansoni infected mice.

The effect of cyclooxygenase-2 (COX-2) inhibitor, such (as meloxicam, and pyocyanin pigment of Pseudomonas aeruginosa) with and without praziquantel (PZQ) on worms, ova count, bone marrow and blood cells in 7 groups of Schistosoma mansoni infected mice was studied. The results revealed significant decrease of worm burden and ova count in all treated groups as compared to the infected untreated group, while those with combined treatment of PZQ and meloxicam or pyocyanin showed complete eradication of the worm with the highest reduction in the tissue egg load. EM showed extensive swelling and vesiculation of the tegument, completely implanted spines that overlie degenerated muscle layer were obvious in groups treated with either meloxicam or pyocyanin. Hematological study revealed significant increase (P<0.05) of total leucocytic count of PZQ treated group while that treated with either meloxicam or pyocyanin showed significant decrease (P<0.05), but in combination of PZQ with meloxicam or pyocyanin no significant difference as compared to the infected untreated group. The neutrophil was the main cell affected in groups treated with neither meloxicam nor pyocyanin alone with significant decrease (P<0.05), but with significant increase (P<0.05) in combination with PZQ as compared to the infected untreated group. Those treated with PZQ plus meloxicam showed significant increase as compared to that plus pyocyanin. Eosinophil count showed significant decrease (P<0.05) in all treated groups as compared to the infected untreated group. Inverse correlation between serum level of sFas and peripheral neutrophil count was detected. Ultrastructural study of the bone marrow explained the results as groups treated with meloxicam revealed dissociation between nuclear and cytoplasmic development in the neutophils with cytoplasm maintaining primitive appearance despite maturation of the nucleus, that is manifested by the persistent production of immature granules and the still orientation of Golgi cternae and the centriole around the nucleus. Groups treated with pyocyanin pigment revealed many abnormalities in neutophils as hypogranularity or early apoptotic morphology changes as intense perinuclear chromatin aggregation or nucleus fragmentation. In peripheral blood apoptotic morphology changes was detected in both groups treated with meloxicam or pyocyanin while most of cells of mice treated with PZQ were in an active state. Consequently, it is preferable to give meloxicam with PZQ for a short period of time (less side-effect) to eradicate S. mansoni worm completely but with continuous observation of the peripheral neutrophil count and function.